I'm a brand new user of Short Cut and CRBasic, and am trying to set up a weather station using a CR1000. I found all my sensors in Short Cut (v 2.5) and generated a wiring diagram. Everything looks good, except Short Cut puts both the temp/RH sensor (HMP35C) and the weather vane (03001) on the same excitation channel (EX1).
Is there a reason for both sensors to be on the same channel? Is there a reason for them to definitely not be on the same channel? I ran the program and both temp and wind direction seem to be reporting correctly, but these sensors are each being excited two times with the set up I have.
I am planning on going into the CRBasic code to change one of the sensors to EX2, but wanted to check if there was a reason for the Short Cut design.
Thanks!
The CR1000 can source 25 mA current from an excitation channel. The HMP35C consumes < 4 mA and the 03001 wind vane consumes < 1 mA so the total is below what the excitation channel can provide. Even though both sensors are being excited at the same time only one is being measured at any given time, and furthermore is being measured using the programmed excitation voltage.
The number of excitation channels on most of our dataloggers is limited compared to the number of signal channels. For that reason it's a good idea to excite more than one sensor with an excitation channel when possible as long as the 25 mA current sourcing capability of the excitation channel isn't exceeded. There are a few sensors that, for reasons other than current sourcing (e.g. "loading" the sensor), you wouldn't want to connect more than one to an excitation channel. For those sensors we've had Short Cut consume the entire excitation channel.
Thank you, that clears it up.